A Computer Implemented Method of Generating a Parametric Structural Design Model

Abstract

This invention relates to a computer implemented method of generating a parametric structural design model from a built structure, a computer program product and an apparatus for performing the method. The computer implemented method comprises the steps of receiving a point cloud (PC) representation of the built structure and thereafter generating a plurality of planes from the PC. Planes that are representative of objects to be included in the model are stored in memory. Other planes that are not representative of objects to be included are discarded. The properties of the objects included in the parametric structural design model are retrieved from an Industry Foundation Classes (IFC) standard and the parametric structural design model is generated with the chosen planes and the properties of those objects from the IFC standard In this way, the generation of the model is more efficient and less computationally burdensome than was heretofore the case.

1 ) A computer implemented method of generating a parametric structural design model from a built structure comprising the steps of:
 receiving a point cloud (PC) representation of the built structure;   generating a plurality of planes from the PC;   determining those planes that are representative of objects to be included in the parametric structural design model and storing those planes in memory;   determining those planes that are not representative of objects to be included in the parametric structural design model and discarding those planes;   retrieving the properties of those objects to be included in the parametric structural design model from an Industry Foundation Classes (IFC) specification containing object property specifications; and   generating the parametric structural design model with the planes representative of the objects to be included, and the properties of those objects from the IFC specification.   
     
     
         2 ) The computer implemented method as claimed in  claim 1  in which the PC contains a data set with a plurality of data points, one or more scan positions, a 3D coordinate value (XYZ), and a scan index value associated therewith. 
     
     
         3 ) The computer implemented method as claimed in  claim 1  in which the method comprises the intermediate step of defining an arrangement graph. 
     
     
         4 ) The computer implemented method as claimed in  claim 3  in which the method comprises the step of generating the parametric structural design model using the arrangement graph. 
     
     
         5 ) The computer implemented method as claimed in  claim 1  in which the method comprises the additional intermediate step of: generating a plurality of IFC structural objects in addition to the walls, the floors and the ceilings, from the PC. 
     
     
         6 ) The computer implemented method as claimed in  claim 5  in which the step of generating the parametric structural design model further comprises generating the parametric structural design model with the plurality of IFC structural objects, and the properties of those objects from the IFC specification. 
     
     
         7 ) The computer implemented method as claimed in  claim 1  in which the parametric structural design model comprises an IFC model including an IFC schema file classifying all object types and object characteristics. 
     
     
         8 ) The computer implemented method as claimed in  claim 1  in which the method comprises the intermediate step of, after receiving the PC, subsampling the PC data points according to a three-dimension (3D) voxel grid. 
     
     
         9 ) The computer implemented method as claimed in  claim 8 , further comprising the steps of: applying a normal estimation function across the subsampled PC data points; and, assigning a 3D normal vector to each data point in addition to their 3D Cartesian coordinate. 
     
     
         10 ) The computer implemented method as claimed in  claim 9 , further comprising the step of planar object recognition including: defining each planar object as the equation of its plane, a surface normal vector and the set of data points that lie on its plane. 
     
     
         11 ) The computer implemented method as claimed in  claim 10  comprising the steps of: defining a projection function from 3D to two dimension (2D) so that a data point may be mapped from 3D onto a flat 2D surface; and defining a reprojection function from 2D to 3D so that the point may be mapped from a 2D plane into 3D space. 
     
     
         12 ) The computer implemented method as claimed in  claim 1  comprising the step of projecting the points associated with a plane to 2D and re-projecting those points back into 3D in order to form the vertices of a simple rectangular collision mesh. 
     
     
         13 ) The computer implemented method as claimed in  claim 1  in which the method comprises the step of collapsing all the data points into a 2D array and applying a Gaussian smoothing technique to the 2D array. 
     
     
         14 ) The computer implemented method as claimed in  claim 1  in which the step of determining the planes not to be included in the parametric structural design model comprises determining those planes that are neither horizontal nor vertical. 
     
     
         15 ) The computer implemented method as claimed in  claim 1  in which the step of determining the planes that are to be included in the parametric structural design model comprises determining those planes that are either vertical or horizontal. 
     
     
         16 ) The computer implemented method as claimed in  claim 15  in which for those planes that are vertical, determining whether the vertical plane relates to one of an internal wall or an external wall. 
     
     
         17 ) The computer implemented method as claimed in  claim 16  in which the step of determining whether the vertical plane relates to an internal wall or an external wall comprises determining whether there is another vertical plane spaced apart from but within a threshold distance from the first vertical plane. 
     
     
         18 ) The computer implemented method as claimed in  claim 1  in which for those planes that are horizontal, determining whether the horizontal plane relates to one of a ceiling, a floor or a slab intermediate floors. 
     
     
         19 ) The computer implemented method as claimed in  claim 18  in which the step of determining whether the horizontal plane relates to a ceiling, a floor or a slab intermediate floors comprises determining whether there is another horizontal plane spaced apart from but within a threshold distance from the first horizontal plane. 
     
     
         20 ) The computer implemented method as claimed in  claim 1  in which the method comprises the additional step of performing structure opening detection. 
     
     
         21 ) (canceled) 
     
     
         22 ) (canceled) 
     
     
         23 ) (canceled) 
     
     
         24 ) (canceled) 
     
     
         25 ) (canceled) 
     
     
         26 ) (canceled)